The invention herein generally involves medical devices, and more particularly concerns devices for the reestablishment of an air passageway through the throat effected initially by the introduction of the device itself followed by intubation, the introduction of an endotracheal tube into the trachea. Such devices are commonly referred to as laryngoscopes and, in use, are intended to provide a direct line viewing or exposure of the larynx by a pushing back or retracting of the tongue, epiglottis and other soft structures within the mouth.
As frequently occurs with a critically ill, anesthetized or injured patient, the normal spontaneous respiratory function is affected and could result in a life threatening situation. Under such circumstances, provision must be made for introducing air into the lungs to prevent suffocation. This is normally effected by the placing of a tube through the mouth and into the larynx or trachea to define an open airway through which the attending person can pump air to inflate the lungs and assist in breathing. The actual introduction of the air can be effected by a manual bag pump, as is frequently used in emergency respiratory equipment, or through use of a mechanical pumping device. In using breathing apparatus, it is essential that the windpipe or trachea be kept clear of food or other substances which might affect the free air flow sought. This function, under normal breathing circumstances, is performed by a fleshy, flap-like cover over the trachea, called the epiglottis.
In situations where an airway must be established and maintained, the patient is most frequently in a semi-conscious or unconscious state, usually lying on his back. Unfortunately, in this position, the lax tongue of the patient tends to fall back into the throat blocking the epiglottis and closing off the windpipe. Therefore, in order to insert the airway or endotracheal tube, the physician frequently relies upon a device called a laryngoscope. The laryngoscope will normally be positioned within the mouth in a manner so as to move the tongue to a non-blocking position, lift the epiglottis away from the windpipe, and provide for a visual view of the opening of the trachea, normally in the vicinity of the vocal chords, to allow for a manual insertion of the endotracheal tube. As will be readily appreciated, it is important that this procedure be performed as rapidly as possible and air flow reestablished and maintained to prevent permanent injury or asphyxiation.
Under current practice, when breathing difficulty occurs, either through injury, illness or when under anesthesia, the patient is, if possible, placed on his back. A breathing device, normally a mask with a connected air bag, is fitted over the patient's mouth and the air bag pumped to force air into the mouth and lungs. However, in most emergencies, adequate breathing cannot be maintained by the bag mask unit and the insertion of an endotracheal tube is usually required. In such cases, the physician or attending person will use the air bag to provide enough air to the lungs to sustain life, and then attempt to insert a laryngoscope to clear a passageway for the subsequent introduction of an endotracheal tube.
While the known art relating to laryngoscopes is quite extensive, the most commonly used laryngoscope is an L-shaped device with a handle section, normally incorporating batteries and being similar in appearance to a flashlight handle. The second section of the device consists of a curved or straight metal blade approximately 10" long and capable of being inserted into the mouth, down the throat and past the epiglottis. Frequently, a light bulb will be provided at the end of the blade. In use, the blade is inserted over the back of the tongue, down the throat and under the epiglottis. The handle is then lifted, lifting the blade, tongue and epiglottis, and thereby unblocking the windpipe opening. Upon obtaining a clear view of the windpipe opening, the tracheal tube is inserted along the laryngoscope blade and the desired flow of air induced through the tube by appropriate mechanical means until such time as the patient is capable of normal breathing.
The use of a conventional laryngoscope involves, at best, a troublesome procedure whereby great care must be taken to avoid internal damage to the mouth and throat membranes while at the same time effectively engaging, moving and maintaining the relatively large tongue mass and epiglottis until such time as the endotracheal tube is intubated. The procedure is frequently complicated by the presence of mucus, blood, vomitus, and the like which must be removed or at least prevented from entrance into the windpipe.
The conventional laryngoscope is also a relatively expensive metal device which is adapted for reuse, and thus gives rise to problems of sterilization. Such problems are increased in those instances wherein a light emitting bulb is provided at the leading end of the blade. The presence of such a bulb at the inserted tip of the laryngoscope may also give rise to the possibility of localized burns to the sensitive membrances.
In view of the generally firm manual manipulation required in the use of a conventional laryngoscope, great care must also be taken to avoid damage to the teeth of the patient.